Question: $ E = \left[\begin{array}{rrr}1 & 1 & 2 \\ 1 & 2 & 0 \\ 1 & 0 & 2\end{array}\right]$ What is $ E^{-1}$ ?
Explanation: $ = \left[\begin{array}{rrr}-2 & 1 & 2 \\ 1 & 0 & -1 \\ 1 & -\frac{1}{2} & -\frac{1}{2}\end{array}\right]$